The following description of background art may include insights, discoveries, understandings or disclosures, or associations together with disclosures not known to the relevant art prior to the present invention but provided by the invention. Some of such contributions of the invention may be specifically pointed out below, whereas other such contributions of the invention will be apparent from their context.
With the ever increasing demand for increasing data rates and higher quality services in the world of mobile communications comes ever increasing demand for better performance of cellular network infrastructures. A wide variety of diverse size of cells and connected devices are proposed in addition to traditional macro and microcells. The available frequency resources are limited and need for efficient use of the resources is essential. Recently the need for more efficient usage of radio resources has brought out an idea of co-existence or sharing of systems meaning that systems share operational resources, for example spectrum in a given region.
In addition, the use of unlicensed frequency bands is proposed. License-exempt (LE) or unlicensed frequency bands are parts of frequency spectrum that are only lightly regulated; users do not need licenses to exploit them. Some of main services using LE spectrum are wireless local area networking technologies, such as wireless local area network (WLAN, WiFi), mesh networks, voice over Internet protocol (VoIP) telephony, etc. Typically a synchronized shared channel is used on these frequency bands. The devices wishing to communicate on the shared channel may be configured to measure interference on the channel prior transmission.